In the manufacture of chain-link fencing and, more generally, long webs of wire mesh, it is known to feed a wire through a machine provided with a worm and mesh blade to form flattened spirals having a pitch angle of about 45.degree., and to cause the advancing spiral to engage in a previously formed spiral. When the length of each spiral is the width of the desired web or fence, the spiral is cut off, the mesh is advanced and the process is repeated.
At the free ends of the spirals and, therefore, the opposite edges of the mesh, adjacent spirals have their wires bent over one another or twisted together to hold them in place. The result is a mesh structure in which each mesh has a substantially square or rectangular configuration. If the pitch angle of the spirals are different from 45.degree., the configuration is that of a rhombus.
Commercial wire mesh webs of the aforedecribed type, according to German Industrial Standard DIN 1199 have a mesh or web width of 2 mm or more and meshes of 10 to 150 mm on a side. The wire diameter may be 1.4 to 3.4 mm and a standard length of the web is 25 m. The web is marketed in the form of a roll or coil and the grid thus produced can be galvanically or otherwise protected against corrosion. Usually, the wires are galvanically plated or are provided with a plastic coating for this purpose.
In accordance with a conventional process, the web is coiled without a core in a stretched state. The resulting roll has the disadvantage that it is not especially compact and relative to the coiled length, requires considerable storage and transport space. This is a consequence of the fact that the stretched web prevents the zigzag-shaped wire spirals of the individual wires from extending deeply one within another.
It has previously been proposed to provide a roll of screening of this type in which the individual wire spirals are compacted together in the plane of the web during the coiling and under the influence of the weight of the individual spirals. In other words, the successive spirals shift together and increase the packing density. The outer turn of the coil is wound in a stretched state to increase the stability of the roll.
While such a roll has a greater compactness than the roll previously descirbed so that it occupies less space during storage and transport, it is incapable of achieving the optiumum packing density because the sucessive wire sprirals lie generally tangential to the roll surface.
A disadvantage common to both of the aforedescribed processes is that the successive turns of the web are easily shiftable relative to one another axially and thus the rolls have low stability with respect to handling.
Especially with the last-mentioned coiling technique, it is found that the rolls can only be uncoiled with difficulty because the twisted together or bent over ends of the wire spirals easily unhook or bind.